As solid-state imaging devices, solid-state imaging devices using CMOS technology are known, and among these, a passive pixel sensor (PPS) type solid-state imaging device is known. The PPS type solid-state imaging device includes a light receiving section in which PPS type pixels including photodiodes each for generating charge of an amount according to an incident light intensity are two-dimensionally arrayed in M rows and N columns, and, in each pixel, accumulates charge generated in the photodiode in response to light incidence in a capacitive element of an integration circuit, and outputs a voltage value according to the accumulated charge amount.
Generally, an output terminal of each of the M pixels of each column is connected with an input terminal of an integration circuit provided corresponding to the column via a readout line provided corresponding to the column. And, in sequence from the first row to the M-th row and row by row, charges generated in the photodiodes of the pixels are input to a corresponding integration circuit through a corresponding readout line, and a voltage value according to the charge amount is output from the integration circuit.
The PPS type solid-state imaging device is used for various purposes. For example, such a solid-state imaging device is used in combination with a scintillator section as an X-ray flat panel also for medical purposes and industrial purposes, and further specifically used also in an X-ray CT apparatus, a microfocus X-ray inspection system, etc. An X-ray inspection system disclosed in Patent Literature 1 is a system that images X-rays output from an X-ray generator and transmitted through an inspection object by a solid-state imaging device to inspect the inspection object, and is capable of imaging X-rays transmitted through the inspection object by the solid-state imaging device in a plurality of types of imaging modes. These multiple types of imaging modes are mutually different in an imaging region in the light receiving section.